1. Field of the Invention
This invention relates to surgical tissue retractors and more particular relates to a small easily manipulated retractor having expandable blades that are for tissue retraction in small incisions such as heart valve surgery.
2. Background Information
There are a number of types of small retractors available for a variety of surgery. For example, there are eye speculum retractors such as the Maumenee-Park eye specular comprised of a pair of parallel blades that expand away from each other and a center blade that can be retracted upward. There are also special retractors that work on the same principle as a compass with a screw member expanding a pair of blades away from each other. For example, a Perkins retractor has a pair of curved arms attached to a scissors-like arrangement that can be locked after opening by operation of the handle.
Another type of small retractor is called a Dingman mouth gag such as that shown and described in U.S. Pat. No. 4,024,859. This device has traversed bar with a centrally mounted tongue retractor and clamp means at opposite ends for adjustably supporting alveolar retractors. There are also mechanically expandable retractors for use in arthroscopic surgery that can be passed through a trocar. The retractor is formed in a long thin tube having a plurality of fingers at the end that can be opened and closed by operation of a trigger-like arrangement at the outer end. The small trigger expandable retractors are generally used for arthroscopic surgery for passing through a puncture. One such device is shown and described in U.S. Pat. No. 5,195,506. While these devices are effective for the specific purpose intended, none of these are entirely suitable for use in small incisions such as those that occur during heart valve surgery.
It is therefore one object of the present invention to provide an improved surgical tissue retractor for use in small incisions in tissue.
Still anther object of the present invention is to provide a surgical tissue retractor having a plurality of expandable blades that may be used in conjunction with a larger retractor.
Still another object of the present invention is to provide a surgical tissue retractor having a plurality of expandable blades that is particularly suited for use in heart valve surgery.
Still another object of the present invention is to provide a surgical tissue retractor having a plurality of expandable blades with the blades being manipulated simultaneously or at least one blade being manipulated independently.
Still another object of the present invention is to provide a surgical tissue retractor having a pair of adjacent blades that expand outwardly and a center blade that can be manipulated independently to retract an incision for desired exposure.
Yet another object of the present invention is to provide a surgical tissue retractor having a plurality of expandable blades with a hanger for securing the tissue retractor to an arm of a larger retractor.